Alternator Suggestions?

[Ronmar]

Thanks Ronmar. I just got done watching and reviewing some material on Lizard Skin products. Very impressive stuff. Just ordered the application kit and buckets of the sound dampening stuff and ceramic heat stuff. I think it will work well in conjunction with some of the other stuff we got. Thank you!

Kevin

Well Thanks, but it was General that suggested it... I have not had a chance to play with it yet

 

[jmak]

Stick with the 260.

What year is your truck? The 260 requires the older trucks to change the mounting of the shock as they have the mounting slung a little farther out. If you cut the huck bolts and make two copies of the spacer plate behind the shock mount out of 1/2" plate you can bolt the shock bracket back in place and it will clear the 260 or the 300.

Don't worry about potential failures - carry a spare VR. The 260 is dead reliable and I've yet to see a confirmed winding or diode failure, etc. Even the VR's are very reliable. In any case if you stick with the 6TL/6TAGM setup you can drive through a whole tank of fuel on just battery if you observe some electrical discipline. And as an overland truck you'll have a secondary solar/generator system that can be shunted over to charge the truck batteries - this gives redundancy so carrying spares or sourcing them during the mission is irrelevant.

Carry a spare starter instead. You aren't push starting this garbage so without a starter you are HOSED. Without an alternator you are just mildly inconvenienced.

Not sure where the concern about the shock tower thing on older trucks is coming from- I have a 98 1078 A0 (3116) and the n1224 dual voltage 260a alt fit with no modifications except creating a new bracket

 

[jmak]

Not sure where the concern about the shock tower thing on older trucks is coming from- I have a 98 1078 A0 and the 260a alt fit with no modifications except creating a new bracket

Here are pics. It was a very easy upgrade from the 100a alt. Only gotcha is the 260a alt seems to use metric for everything- the spindle nut was M20-1.5, not 3/4 like the 100a. They are very close, like a millimeter different. Not an issue if your 260a has a pullly/nut with it

 

[Kevin Means]

Wow! That's a big help jmak. Thank you. I see your 260 is right up against that "boot" that connects to the exhaust. I unbolted mine and moved it over as far as I could, and it looks like it will be OK, but just barely. I'm assuming you've experienced no problems?

The voltage regulator on my 260 has a completely different plug than the stock 100. I'd love to see some details on how you wired it.

Kevin

 

[jmak]

Wow! That's a big help jmak. Thank you. I see your 260 is right up against that "boot" that connects to the exhaust. I unbolted mine and moved it over as far as I could, and it looks like it will be OK, but just barely. I'm assuming you've experienced no problems?

The voltage regulator on my 260 has a completely different plug than the stock 100. I'd love to see some details on how you wired it.

Kevin

It's not touching the boot, but even if it was it's just the protective shroud around the fan blade so should be fine.. been a few hundred miles since install and no issues so far.

The reg shouldn't be an issue- I was worried for a second too, but it only connects to the alternator itself aside from the two wires that go to studs, so no prob. I didn't have to relocate the reg either, just had to remove it to tighten down the alternator then bolt it back on.

Very easy install! Worst part was taking things apart to do the water pump belt at the same time, and that really wasn't bad either.

Oh- I did have to cut and re-terminate some of the original smaller wires because their eyelets were too small for the larger bolts of the 260a alt. 3/8 eyelets and a metric bolt kit that has m6/M8/m10 and you should be good

 

[jmak]

Chatting with OP a bit in dms, looks like we had some confusion.. he has a n1243-6 260a 28v only alternator. Mine is the n1224 260a dual voltage that is used in newer fmtvs/mraps. I have no idea which vehicles use the n1243 or if it will fit

 

[GeneralDisorder]

Ah yes the 1224 is the FMTV 260A dual-volt. A single voltage 260 would be significantly smaller and likely easier to fit.

 

[jmak]

Ah yes the 1224 is the FMTV 260A dual-volt. A single voltage 260 would be significantly smaller and likely easier to fit.

To be clear- I have the n1224 dual voltage and installed it on my 98 1078A0 with a 3116 engine. It fits great- no modifications needed. Someone on a Facebook post about it said if you get a full install kit with the official bracket that may be when you run into the shock tower issue. I have zero fitment issues with the cheap/easy bracket I made. My 260a was missing the pulley too- I was able to use the pulley from the 100a alt, it just needed a larger m20 spindle nut and a larger washer

 

[GeneralDisorder]

To be clear- I have the n1224 dual voltage and installed it on my 98 1078A0 with a 3116 engine. It fits great- no modifications needed. Someone on a Facebook post about it said if you get a full install kit with the official bracket that may be when you run into the shock tower issue. I have zero fitment issues with the cheap/easy bracket I made

The kit slings the alternator out further to get more belt wrap. The 260 and 300 when loaded can barely operate without belt slip as it is. Having the alt too close to the engine reduces wrap on the pulley and thus power transfer. They already slip when heavily loaded, or when the belt is old, or wet, or slightly loose - which all vee belts almost always are. The serpentine system is *better* but doesn't entirely solve it. The belt needs to be 2-3 ribs wider like it is on the 540A MRAP units, etc.

I would be concerned that my high amperage alternator isn't really all that high and won't really provide when needed due to slippage issues. There's typically a reason behind these decisions and it wasn't just a concern of fitting it in the space - the engine has to effectively spin it too.

 

[jmak]

The kit slings the alternator out further to get more belt wrap. The 260 and 300 when loaded can barely operate without belt slip as it is. Having the alt too close to the engine reduces wrap on the pulley and thus power transfer. They already slip when heavily loaded, or when the belt is old, or wet, or slightly loose - which all vee belts almost always are. The serpentine system is *better* but doesn't entirely solve it. The belt needs to be 2-3 ribs wider like it is on the 540A MRAP units, etc.

I would be concerned that my high amperage alternator isn't really all that high and won't really provide when needed due to slippage issues. There's typically a reason behind these decisions and it wasn't just a concern of fitting it in the space - the engine has to effectively spin it too.

Ah, gotcha. Someone else mentioned slippage concerns too. It's definitely slipping a bit as I noticed the belt labels were no longer aligned with each other after running it. I wasn't getting anything out of my original alternator likely due to a bad regulator, so I'm not super concerned.. maybe worth revisiting and trying to come up with a better tensioning system or different pulleys/belts if I ever add house batteries. It's working well enough to keep the output voltage high enough and keep four batteries charged, so I'm stoked to be saved from plugging into a trickle charger constantly for now.

 

[GeneralDisorder]

The truck itself draws very little power so I wouldn't expect it to be an issue at at the moment. It WILL present to you when the temp drops if you have a grid heater - those draw something like 90 amps at 28v and will load the cold alternator and belt that are both ~15 degrees and the belts will absolutely wake the dead with their protest.

Same thing happens if they are loaded down against a battery bank but you can somewhat better control when that occurs.